Add meta parameter support to tools, resources, templates, and prompts decorators (#1294)

docs/servers/prompts.mdx

@@ -65,7 +65,8 @@ While FastMCP infers the name and description from your function, you can overri
 @mcp.prompt(
     name="analyze_data_request",          # Custom prompt name
     description="Creates a request to analyze data with specific parameters",  # Custom description
-    tags={"analysis", "data"}             # Optional categorization tags
+    tags={"analysis", "data"},            # Optional categorization tags
+    meta={"version": "1.1", "author": "data-team"}  # Custom metadata
 )
 def data_analysis_prompt(
     data_uri: str = Field(description="The URI of the resource containing the data."),
@@ -91,6 +92,12 @@ def data_analysis_prompt(
 <ParamField body="enabled" type="bool" default="True">
   A boolean to enable or disable the prompt. See [Disabling Prompts](#disabling-prompts) for more information
 </ParamField>
+
+<ParamField body="meta" type="dict[str, Any] | None">
+  <VersionBadge version="2.11.0" />
+  
+  Optional meta information about the prompt. This data is passed through to the MCP client as the `_meta` field of the client-side prompt object and can be used for custom metadata, versioning, or other application-specific purposes.
+</ParamField>
 </Card>
 
 ### Argument Types

docs/servers/resources.mdx

@@ -73,7 +73,8 @@ mcp = FastMCP(name="DataServer")
     name="ApplicationStatus",     # Custom name
     description="Provides the current status of the application.", # Custom description
     mime_type="application/json", # Explicit MIME type
-    tags={"monitoring", "status"} # Categorization tags
+    tags={"monitoring", "status"}, # Categorization tags
+    meta={"version": "2.1", "team": "infrastructure"}  # Custom metadata
 )
 def get_application_status() -> dict:
     """Internal function description (ignored if description is provided above)."""
@@ -116,6 +117,12 @@ def get_application_status() -> dict:
     </ParamField>
   </Expandable>
 </ParamField>
+
+<ParamField body="meta" type="dict[str, Any] | None">
+  <VersionBadge version="2.11.0" />
+  
+  Optional meta information about the resource. This data is passed through to the MCP client as the `_meta` field of the client-side resource object and can be used for custom metadata, versioning, or other application-specific purposes.
+</ParamField>
 </Card>
 
 ### Return Values

docs/servers/tools.mdx

@@ -58,6 +58,7 @@ While FastMCP infers the name and description from your function, you can overri
     name="find_products",           # Custom tool name for the LLM
     description="Search the product catalog with optional category filtering.", # Custom description
     tags={"catalog", "search"},      # Optional tags for organization/filtering
+    meta={"version": "1.2", "author": "product-team"}  # Custom metadata
 )
 def search_products_implementation(query: str, category: str | None = None) -> list[dict]:
     """Internal function description (ignored if description is provided above)."""
@@ -107,6 +108,12 @@ def search_products_implementation(query: str, category: str | None = None) -> l
     </ParamField>
   </Expandable>
 </ParamField>
+
+<ParamField body="meta" type="dict[str, Any] | None">
+  <VersionBadge version="2.11.0" />
+  
+  Optional meta information about the tool. This data is passed through to the MCP client as the `_meta` field of the client-side tool object and can be used for custom metadata, versioning, or other application-specific purposes.
+</ParamField>
 </Card>
 
 

src/fastmcp/prompts/prompt.py

@@ -117,6 +117,7 @@ class Prompt(FastMCPComponent, ABC):
         description: str | None = None,
         tags: set[str] | None = None,
         enabled: bool | None = None,
+        meta: dict[str, Any] | None = None,
     ) -> FunctionPrompt:
         """Create a Prompt from a function.
 
@@ -133,6 +134,7 @@ class Prompt(FastMCPComponent, ABC):
             description=description,
             tags=tags,
             enabled=enabled,
+            meta=meta,
         )
 
     @abstractmethod
@@ -158,6 +160,7 @@ class FunctionPrompt(Prompt):
         description: str | None = None,
         tags: set[str] | None = None,
         enabled: bool | None = None,
+        meta: dict[str, Any] | None = None,
     ) -> FunctionPrompt:
         """Create a Prompt from a function.
 
@@ -252,6 +255,7 @@ class FunctionPrompt(Prompt):
             tags=tags or set(),
             enabled=enabled if enabled is not None else True,
             fn=fn,
+            meta=meta,
         )
 
     def _convert_string_arguments(self, kwargs: dict[str, Any]) -> dict[str, Any]:

src/fastmcp/resources/resource.py

@@ -76,6 +76,7 @@ class Resource(FastMCPComponent, abc.ABC):
         tags: set[str] | None = None,
         enabled: bool | None = None,
         annotations: Annotations | None = None,
+        meta: dict[str, Any] | None = None,
     ) -> FunctionResource:
         return FunctionResource.from_function(
             fn=fn,
@@ -87,6 +88,7 @@ class Resource(FastMCPComponent, abc.ABC):
             tags=tags,
             enabled=enabled,
             annotations=annotations,
+            meta=meta,
         )
 
     @field_validator("mime_type", mode="before")
@@ -172,6 +174,7 @@ class FunctionResource(Resource):
         tags: set[str] | None = None,
         enabled: bool | None = None,
         annotations: Annotations | None = None,
+        meta: dict[str, Any] | None = None,
     ) -> FunctionResource:
         """Create a FunctionResource from a function."""
         if isinstance(uri, str):
@@ -186,6 +189,7 @@ class FunctionResource(Resource):
             tags=tags or set(),
             enabled=enabled if enabled is not None else True,
             annotations=annotations,
+            meta=meta,
         )
 
     async def read(self) -> str | bytes:

src/fastmcp/resources/template.py

@@ -96,6 +96,7 @@ class ResourceTemplate(FastMCPComponent):
         tags: set[str] | None = None,
         enabled: bool | None = None,
         annotations: Annotations | None = None,
+        meta: dict[str, Any] | None = None,
     ) -> FunctionResourceTemplate:
         return FunctionResourceTemplate.from_function(
             fn=fn,
@@ -107,6 +108,7 @@ class ResourceTemplate(FastMCPComponent):
             tags=tags,
             enabled=enabled,
             annotations=annotations,
+            meta=meta,
         )
 
     @field_validator("mime_type", mode="before")
@@ -219,6 +221,7 @@ class FunctionResourceTemplate(ResourceTemplate):
         tags: set[str] | None = None,
         enabled: bool | None = None,
         annotations: Annotations | None = None,
+        meta: dict[str, Any] | None = None,
     ) -> FunctionResourceTemplate:
         """Create a template from a function."""
         from fastmcp.server.context import Context
@@ -304,4 +307,5 @@ class FunctionResourceTemplate(ResourceTemplate):
             tags=tags or set(),
             enabled=enabled if enabled is not None else True,
             annotations=annotations,
+            meta=meta,
         )

src/fastmcp/server/server.py

@@ -871,6 +871,7 @@ class FastMCP(Generic[LifespanResultT]):
         output_schema: dict[str, Any] | None | NotSetT = NotSet,
         annotations: ToolAnnotations | dict[str, Any] | None = None,
         exclude_args: list[str] | None = None,
+        meta: dict[str, Any] | None = None,
         enabled: bool | None = None,
     ) -> FunctionTool: ...
 
@@ -886,6 +887,7 @@ class FastMCP(Generic[LifespanResultT]):
         output_schema: dict[str, Any] | None | NotSetT = NotSet,
         annotations: ToolAnnotations | dict[str, Any] | None = None,
         exclude_args: list[str] | None = None,
+        meta: dict[str, Any] | None = None,
         enabled: bool | None = None,
     ) -> Callable[[AnyFunction], FunctionTool]: ...
 
@@ -900,6 +902,7 @@ class FastMCP(Generic[LifespanResultT]):
         output_schema: dict[str, Any] | None | NotSetT = NotSet,
         annotations: ToolAnnotations | dict[str, Any] | None = None,
         exclude_args: list[str] | None = None,
+        meta: dict[str, Any] | None = None,
         enabled: bool | None = None,
     ) -> Callable[[AnyFunction], FunctionTool] | FunctionTool:
         """Decorator to register a tool.
@@ -923,6 +926,7 @@ class FastMCP(Generic[LifespanResultT]):
             output_schema: Optional JSON schema for the tool's output
             annotations: Optional annotations about the tool's behavior
             exclude_args: Optional list of argument names to exclude from the tool schema
+            meta: Optional meta information about the tool
             enabled: Optional boolean to enable or disable the tool
 
         Examples:
@@ -981,6 +985,7 @@ class FastMCP(Generic[LifespanResultT]):
                 output_schema=output_schema,
                 annotations=annotations,
                 exclude_args=exclude_args,
+                meta=meta,
                 serializer=self._tool_serializer,
                 enabled=enabled,
             )
@@ -1013,6 +1018,7 @@ class FastMCP(Generic[LifespanResultT]):
             output_schema=output_schema,
             annotations=annotations,
             exclude_args=exclude_args,
+            meta=meta,
             enabled=enabled,
         )
 
@@ -1111,6 +1117,7 @@ class FastMCP(Generic[LifespanResultT]):
         tags: set[str] | None = None,
         enabled: bool | None = None,
         annotations: Annotations | dict[str, Any] | None = None,
+        meta: dict[str, Any] | None = None,
     ) -> Callable[[AnyFunction], Resource | ResourceTemplate]:
         """Decorator to register a function as a resource.
 
@@ -1135,6 +1142,7 @@ class FastMCP(Generic[LifespanResultT]):
             tags: Optional set of tags for categorizing the resource
             enabled: Optional boolean to enable or disable the resource
             annotations: Optional annotations about the resource's behavior
+            meta: Optional meta information about the resource
 
         Examples:
             Register a resource with a custom name:
@@ -1208,6 +1216,7 @@ class FastMCP(Generic[LifespanResultT]):
                     tags=tags,
                     enabled=enabled,
                     annotations=annotations,
+                    meta=meta,
                 )
                 self.add_template(template)
                 return template
@@ -1222,6 +1231,7 @@ class FastMCP(Generic[LifespanResultT]):
                     tags=tags,
                     enabled=enabled,
                     annotations=annotations,
+                    meta=meta,
                 )
                 self.add_resource(resource)
                 return resource
@@ -1266,6 +1276,7 @@ class FastMCP(Generic[LifespanResultT]):
         description: str | None = None,
         tags: set[str] | None = None,
         enabled: bool | None = None,
+        meta: dict[str, Any] | None = None,
     ) -> FunctionPrompt: ...
 
     @overload
@@ -1278,6 +1289,7 @@ class FastMCP(Generic[LifespanResultT]):
         description: str | None = None,
         tags: set[str] | None = None,
         enabled: bool | None = None,
+        meta: dict[str, Any] | None = None,
     ) -> Callable[[AnyFunction], FunctionPrompt]: ...
 
     def prompt(
@@ -1289,6 +1301,7 @@ class FastMCP(Generic[LifespanResultT]):
         description: str | None = None,
         tags: set[str] | None = None,
         enabled: bool | None = None,
+        meta: dict[str, Any] | None = None,
     ) -> Callable[[AnyFunction], FunctionPrompt] | FunctionPrompt:
         """Decorator to register a prompt.
 
@@ -1309,6 +1322,7 @@ class FastMCP(Generic[LifespanResultT]):
             description: Optional description of what the prompt does
             tags: Optional set of tags for categorizing the prompt
             enabled: Optional boolean to enable or disable the prompt
+            meta: Optional meta information about the prompt
 
         Examples:
 
@@ -1386,6 +1400,7 @@ class FastMCP(Generic[LifespanResultT]):
                 description=description,
                 tags=tags,
                 enabled=enabled,
+                meta=meta,
             )
             self.add_prompt(prompt)
 
@@ -1415,6 +1430,7 @@ class FastMCP(Generic[LifespanResultT]):
             description=description,
             tags=tags,
             enabled=enabled,
+            meta=meta,
         )
 
     async def run_stdio_async(self, show_banner: bool = True) -> None:

src/fastmcp/tools/tool.py

@@ -165,6 +165,7 @@ class Tool(FastMCPComponent):
         exclude_args: list[str] | None = None,
         output_schema: dict[str, Any] | None | NotSetT | Literal[False] = NotSet,
         serializer: Callable[[Any], str] | None = None,
+        meta: dict[str, Any] | None = None,
         enabled: bool | None = None,
     ) -> FunctionTool:
         """Create a Tool from a function."""
@@ -178,6 +179,7 @@ class Tool(FastMCPComponent):
             exclude_args=exclude_args,
             output_schema=output_schema,
             serializer=serializer,
+            meta=meta,
             enabled=enabled,
         )
 
@@ -240,6 +242,7 @@ class FunctionTool(Tool):
         exclude_args: list[str] | None = None,
         output_schema: dict[str, Any] | None | NotSetT | Literal[False] = NotSet,
         serializer: Callable[[Any], str] | None = None,
+        meta: dict[str, Any] | None = None,
         enabled: bool | None = None,
     ) -> FunctionTool:
         """Create a Tool from a function."""
@@ -272,6 +275,7 @@ class FunctionTool(Tool):
             annotations=annotations,
             tags=tags or set(),
             serializer=serializer,
+            meta=meta,
             enabled=enabled if enabled is not None else True,
         )
 

tests/prompts/test_prompt.py

@@ -482,3 +482,18 @@ class TestPromptArgumentDescriptions:
                     "Provide as a JSON string matching the following schema:"
                     not in arg.description
                 )
+
+    def test_prompt_meta_parameter(self):
+        """Test that meta parameter is properly handled."""
+
+        def test_prompt(message: str) -> str:
+            return f"Response: {message}"
+
+        meta_data = {"version": "3.0", "type": "prompt"}
+        prompt = Prompt.from_function(test_prompt, meta=meta_data)
+
+        assert prompt.meta == meta_data
+        mcp_prompt = prompt.to_mcp_prompt()
+        # MCP prompt includes fastmcp meta, so check that our meta is included
+        assert mcp_prompt.meta is not None
+        assert meta_data.items() <= mcp_prompt.meta.items()

tests/resources/test_resource_template_meta.py

@@ -0,0 +1,25 @@
+from fastmcp.resources import ResourceTemplate
+
+
+class TestResourceTemplateMeta:
+    """Test ResourceTemplate meta functionality."""
+
+    def test_template_meta_parameter(self):
+        """Test that meta parameter is properly handled."""
+
+        def template_func(param: str) -> str:
+            return f"Result: {param}"
+
+        meta_data = {"version": "2.0", "template": "test"}
+        template = ResourceTemplate.from_function(
+            fn=template_func,
+            uri_template="test://{param}",
+            name="test_template",
+            meta=meta_data,
+        )
+
+        assert template.meta == meta_data
+        mcp_template = template.to_mcp_template()
+        # MCP template includes fastmcp meta, so check that our meta is included
+        assert mcp_template.meta is not None
+        assert meta_data.items() <= mcp_template.meta.items()

tests/resources/test_resources.py

@@ -93,3 +93,23 @@ class TestResourceValidation:
 
         with pytest.raises(TypeError, match="abstract method"):
             ConcreteResource(uri=AnyUrl("test://test"), name="test")  # type: ignore
+
+    def test_resource_meta_parameter(self):
+        """Test that meta parameter is properly handled."""
+
+        def resource_func() -> str:
+            return "test content"
+
+        meta_data = {"version": "1.0", "category": "test"}
+        resource = Resource.from_function(
+            fn=resource_func,
+            uri="resource://test",
+            name="test_resource",
+            meta=meta_data,
+        )
+
+        assert resource.meta == meta_data
+        mcp_resource = resource.to_mcp_resource()
+        # MCP resource includes fastmcp meta, so check that our meta is included
+        assert mcp_resource.meta is not None
+        assert meta_data.items() <= mcp_resource.meta.items()

tests/server/test_server.py

@@ -421,6 +421,22 @@ class TestToolDecorator:
             def my_function(x: int) -> str:
                 return f"Result: {x}"
 
+    async def test_tool_decorator_with_meta(self):
+        """Test that meta parameter is passed through the tool decorator."""
+        mcp = FastMCP()
+
+        meta_data = {"version": "1.0", "author": "test"}
+
+        @mcp.tool(meta=meta_data)
+        def multiply(a: int, b: int) -> int:
+            """Multiply two numbers."""
+            return a * b
+
+        tools_dict = await mcp.get_tools()
+        tool = tools_dict["multiply"]
+
+        assert tool.meta == meta_data
+
 
 class TestResourceDecorator:
     async def test_no_resources_before_decorator(self):
@@ -584,6 +600,21 @@ class TestResourceDecorator:
             result = await client.read_resource("resource://data")
             assert result[0].text == "Static Hello, world!"  # type: ignore[attr-defined]
 
+    async def test_resource_decorator_with_meta(self):
+        """Test that meta parameter is passed through the resource decorator."""
+        mcp = FastMCP()
+
+        meta_data = {"version": "1.0", "author": "test"}
+
+        @mcp.resource("resource://data", meta=meta_data)
+        def get_data() -> str:
+            return "Hello, world!"
+
+        resources_dict = await mcp.get_resources()
+        resource = resources_dict["resource://data"]
+
+        assert resource.meta == meta_data
+
 
 class TestTemplateDecorator:
     async def test_template_decorator(self):
@@ -733,6 +764,21 @@ class TestTemplateDecorator:
         assert template.uri_template == "resource://{param*}"
         assert template.name == "template_resource"
 
+    async def test_template_decorator_with_meta(self):
+        """Test that meta parameter is passed through the template decorator."""
+        mcp = FastMCP()
+
+        meta_data = {"version": "2.0", "template": "test"}
+
+        @mcp.resource("resource://{param}/data", meta=meta_data)
+        def get_template_data(param: str) -> str:
+            return f"Data for {param}"
+
+        templates_dict = await mcp.get_resource_templates()
+        template = templates_dict["resource://{param}/data"]
+
+        assert template.meta == meta_data
+
 
 class TestPromptDecorator:
     async def test_prompt_decorator(self):
@@ -988,6 +1034,21 @@ class TestPromptDecorator:
             message = result.messages[0]
             assert message.content.text == "Static Hello, world!"  # type: ignore[attr-defined]
 
+    async def test_prompt_decorator_with_meta(self):
+        """Test that meta parameter is passed through the prompt decorator."""
+        mcp = FastMCP()
+
+        meta_data = {"version": "3.0", "type": "prompt"}
+
+        @mcp.prompt(meta=meta_data)
+        def test_prompt(message: str) -> str:
+            return f"Response: {message}"
+
+        prompts_dict = await mcp.get_prompts()
+        prompt = prompts_dict["test_prompt"]
+
+        assert prompt.meta == meta_data
+
 
 class TestResourcePrefixHelpers:
     @pytest.mark.parametrize(

tests/tools/test_tool.py

@@ -44,6 +44,22 @@ class TestToolFromFunction:
         }
         assert tool.output_schema == expected_schema
 
+    def test_meta_parameter(self):
+        """Test that meta parameter is properly handled."""
+
+        def multiply(a: int, b: int) -> int:
+            """Multiply two numbers."""
+            return a * b
+
+        meta_data = {"version": "1.0", "author": "test"}
+        tool = Tool.from_function(multiply, meta=meta_data)
+
+        assert tool.meta == meta_data
+        mcp_tool = tool.to_mcp_tool()
+        # MCP tool includes fastmcp meta, so check that our meta is included
+        assert mcp_tool.meta is not None
+        assert meta_data.items() <= mcp_tool.meta.items()
+
     async def test_async_function(self):
         """Test registering and running an async function."""